One vertex per element, one color per generator, with an edge from x to x·s.
(9,10)(11,17)(12,15)(13,16)(14,19)(18,23)(20,22)(21,24)(25,26)(27,37)(28,34)(29,36)(30,32)(31,35)(33,39)(38,51)(40,49)(41,46)(42,50)(43,45)(44,48)(47,54)(52,56)(53,55) involution — undirected(1,2)(3,7)(4,6)(5,8)(9,11,13,19)(10,14,16,17)(12,20,21,18)(15,23,24,22)(26,32)(28,41)(33,45)(35,36)(37,49)(38,52)(42,44)(53,54)(1,3)(2,5)(4,8)(6,7)(25,27,31,39,30,40,29,43)(26,33,36,37,32,45,35,49)(28,38,42,54,41,52,44,53)(34,47,48,51,46,55,50,56)(2,6)(3,8)(9,12,13,21)(10,15,16,24)(11,18,19,20)(14,22,17,23)(25,28)(26,34)(27,38)(29,44)(30,41)(31,42)(32,46)(33,47)(35,50)(36,48)(37,51)(39,54)(40,52)(43,53)(45,55)(49,56)(2,6)(5,7)(10,16)(14,17)(15,24)(22,23)(25,29,30,31)(26,35,32,36)(27,39,40,43)(28,42,41,44)(33,37,45,49)(34,48,46,50)(38,53,52,54)(47,56,55,51)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.